Re: [Tutor] Fetching dictionaries using MySQLdb
Hi Danny, Danny Yoo wrote on 08.08.2005: >On Mon, 8 Aug 2005, Jan Eden wrote: > >>Is there a recommended way to receive the results of an SQL query >>in the form I need? Or do I have to create a dictionary of >>fieldname tuples which can be zipped with the query result tuple? > > >Hi Jan, > >MySQLdb supports the concept of customized cursor types. They have >a particular cursor class that returns dictionary objects: Great! I found the pydoc for MySQLdb a bit confusing and would probably have taken quite a while to figure that out - thanks a lot. - Jan -- Any technology which is distinguishable from magic is insufficiently advanced. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Fetching dictionaries using MySQLdb
On Mon, 8 Aug 2005, Jan Eden wrote:
> Is there a recommended way to receive the results of an SQL query in the
> form I need? Or do I have to create a dictionary of fieldname tuples
> which can be zipped with the query result tuple?
Hi Jan,
MySQLdb supports the concept of customized cursor types. They have a
particular cursor class that returns dictionary objects:
##
>>> import MySQLdb
>>> import MySQLdb.cursors
>>> MySQLdb.cursors.DictCursor
##
When we construct a connection object, we can tell MySQL to construct
those kind of custom cursors by default:
##
>>> conn = MySQLdb.connect(db='test_adb',
...cursorclass=MySQLdb.cursors.DictCursor)
>>> cursor = conn.cursor()
>>> cursor.execute("""select name, start_coordinate,
...end_coordinate
... from BAC""")
1624L
>>>
>>> cursor.fetchone()
{'name': 'F10A5', 'end_coordinate': 28462975L, 'start_coordinate':
28333429L}
>>> cursor.fetchone()
{'name': 'T12M4', 'end_coordinate': 3002250L, 'start_coordinate':
2942990L}
>>> cursor.fetchone()
{'name': 'T12I7', 'end_coordinate': 24869607L, 'start_coordinate':
24834300L}
##
Good luck!
___
Tutor maillist - Tutor@python.org
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Re: [Tutor] Fetching dictionaries using MySQLdb
Kent Johnson wrote on 08.08.2005: >Jan Eden wrote: >>The documentation for MySQLdb says that fetchoneDict() is >>deprecated and the usage of fetchone() is suggested. > >You could just use fetchoneDict(); deprecated isn't the same as >gone... I tend to avoid deprecated functions/methods - I would need another method sooner or later anyway. >> >>Is there a recommended way to receive the results of an SQL query >>in the form I need? Or do I have to create a dictionary of >>fieldname tuples which can be zipped with the query result tuple? > >You can create a list of field names from the cursor.description >attribute. But if the number of fields in the result varies how do >you know which field goes with which description? > That works, thank you. I will use the cursor.description attribute immediately after executing a query, so it will contain the correct field descriptions whenever I need them. The rest of my program uses the type attribute to decide which fields are present and which are not. All this is part of a port from Perl to Python - I will publish a log of everything I encountered in a couple of weeks. Cheers, Jan -- There's no place like ~/ ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Fetching dictionaries using MySQLdb
Jan Eden wrote: > Hi, > > in Perl's DBI, I used fetchrow_hashref() to receive a database row as > a dictionary, with the field names being the dictionary keys. > > MySQLdb's fetchone() returns a tuple Unfortunately, I have a > dictionary of SQL queries which return rows of different lengths > (read: with a varying number of fields). > > The documentation for MySQLdb says that fetchoneDict() is deprecated > and the usage of fetchone() is suggested. You could just use fetchoneDict(); deprecated isn't the same as gone... > > Is there a recommended way to receive the results of an SQL query in > the form I need? Or do I have to create a dictionary of fieldname > tuples which can be zipped with the query result tuple? You can create a list of field names from the cursor.description attribute. But if the number of fields in the result varies how do you know which field goes with which description? Kent ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] Fetching dictionaries using MySQLdb
Hi, in Perl's DBI, I used fetchrow_hashref() to receive a database row as a dictionary, with the field names being the dictionary keys. MySQLdb's fetchone() returns a tuple Unfortunately, I have a dictionary of SQL queries which return rows of different lengths (read: with a varying number of fields). The documentation for MySQLdb says that fetchoneDict() is deprecated and the usage of fetchone() is suggested. Is there a recommended way to receive the results of an SQL query in the form I need? Or do I have to create a dictionary of fieldname tuples which can be zipped with the query result tuple? Thanks, Jan -- Any sufficiently advanced technology is indistinguishable from a Perl script. - Programming Perl ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
